[915] Miyoshi 1901.

[916] Darbishire 1897, p. 657.

[917] Beckmann 1907.

[918] Bitter 1899.

[919] Peirce 1898.

[920] Schrenk 1898.

[921] Elenkin 1901.

[922] See Chap. X.

[923] Mereschkovsky 1918.

[924] Meyer 1825, p. 44.